Dataset Information

Nusinersen for Spinal Muscular Atrophy in the United States: Findings From a Retrospective Claims Database Analysis

ABSTRACT:

Introduction

Spinal muscular atrophy (SMA) is a rare, genetic neuromuscular disorder caused by deletion/mutation of the survival motor neuron 1 gene, characterized by progressive loss of motor neurons, resulting in increasing muscular weakness, deteriorating motor function, and, in its most severe form, death before 2 years. Nusinersen, an antisense oligonucleotide that increases expression of the functional SMN protein, was approved for SMA by US and European regulatory agencies in 2016 and 2017, respectively. The indicated regimen requires intrathecal injections every 4 months, following the first four injections during the loading phase. Adherence is integral to treatment success. Adherence to nusinersen may pose particular challenges as most patients with SMA are young children who require complex multidisciplinary care (including ongoing intrathecal treatment administration and potential specialized anesthetic and surgical procedures) at specialized centers. However, real-world data on adherence to nusinersen are limited.

Methods

We conducted a retrospective claims database analysis from December 23, 2016, to November 20, 2019, to study nusinersen adherence and discontinuation/persistence in US patients with SMA types 1–3 who completed the loading phase, and to determine the impact of non-adherence or treatment discontinuation on SMA-related comorbidities, health care resource utilization (HCRU), and costs.

Results

We identified 23 patients with SMA type 1, 41 patients with SMA type 2, and 260 patients with SMA type 3 who had completed the loading phase. Deviations from the indicated nusinersen treatment schedule were frequent in real-world usage, with most patients receiving ≥1 dose outside the scheduled interval. Across SMA types, non-adherent patients were more likely to have had SMA-related comorbidities (e.g., feeding difficulties, dyspnea and respiratory anomalies, and muscle weakness) and greater HCRU. Persistence rates 12 months after treatment initiation for patients with SMA types 1, 2, and 3 were 55.2%, 42.4%, and 54.6%, respectively. Patients who discontinued nusinersen and those who did not had generally similar comorbidity profiles. Discontinuation was associated with greater health care costs across SMA types.

Conclusion

Our analysis of claims data indicated that discontinuation and non-adherence to nusinersen treatment were prevalent, and associated with greater frequency of comorbidities, greater HCRU, and increased costs for patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01938-w.

SUBMITTER: Gauthier-Loiselle M

PROVIDER: S-EPMC8552979 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:IntroductionSpinal muscular atrophy (SMA) is a neurogenic disorder associated with progressive loss of muscle function, respiratory failure, and premature mortality. This study aimed to describe and compare real-world health care resource utilization (HCRU) and costs for US patients with SMA treated with disease-modifying treatments, including onasemnogene abeparvovec, nusinersen, and/or risdiplam.MethodsThis study used claims and structured electronic medical record data from the HealthVerity claims database (January 1, 2017-March 31, 2021). Eligible patients were aged ≤ 2 years at index (treatment initiation or switch), diagnosed with SMA, had ≥ 1 pharmacy/medical claim for onasemnogene abeparvovec, nusinersen, and/or risdiplam, and continuous enrollment ≥ 1 month pre- and ≥ 2 months post-index. SMA-related HCRU and costs during the study period (> 12 months post-index) were compared between treatment groups before and after propensity score weighting. Costs were adjusted to 2021 USD.ResultsOf 74 included patients, 62 (83.8%) received nusinersen and 12 (16.2%) received onasemnogene abeparvovec (monotherapy, n = 9; onasemnogene abeparvovec after nusinersen [switching], n = 3). After weighting, nusinersen-treated patients had greater annual numbers of inpatient (mean 5.3 nusinersen vs. 1.8 onasemnogene abeparvovec) and emergency department (mean 3.0 nusinersen vs. 1.5 onasemnogene abeparvovec; p < 0.05) visits, and greater annual SMA-related medical costs (mean $78,446 nusinersen vs. $29,438 onasemnogene abeparvovec; mean difference $49,007, p < 0.05) than onasemnogene abeparvovec-treated patients. Onasemnogene abeparvovec-treated patients incurred greater SMA-treatment pharmacy costs than nusinersen-treated patients (mean $2,241,875 onasemnogene abeparvovec vs. $693,191 nusinersen; mean difference $1,548,684, p < 0.05).ConclusionsSMA is associated with substantial economic burden. Patients treated with onasemnogene abeparvovec had greater SMA treatment-related pharmacy costs but lower SMA-related HCRU and medical costs compared with patients receiving nusinersen monotherapy.

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